Maintenance of the process components and the pipe conduits interconnecting the same must be carried out by remote control in radioactively contaminated shielded cells in the nuclear field such as large-area cells in nuclear reprocessing facilities. For maintaining the conduits, it can be necessary for a leaky portion of the conduit to be cut out of a conduit and replaced by a replacement conduit segment which is welded into the conduit by remote manipulation. The replacement conduit segment is prepared outside the cell and, before it can be welded into place, the two sawn end faces of the conduit must be machined. The replacement conduit segment must correspond in length to the inner gap between the two end faces of the end portions of the cut conduit.